First of all, I do not think this will happen, but we have to leave open all possible scenarios.
If this corona virus spreads to the US, we can expect the US market to tank like the Chinese market. The most likely pattern being the fall 2018 rate panic tank.
I do not see this happening because Trump and his buddies are already taking extreme measures including: - Suspending US entry from China for non-citizens - Mandatory 14 day quarantine (The last mandatory quarantine was for SMALLPOX)
IF it spreads though, the market tanks hard. This virus is basically shutting China down, and if it happens here the economy is screwed because it will devastate the service sector.
Not gonna bother posting other indices, you guys get the picture. In any case, I am going conservative with any long plays until this whole virus scare is over. Small positions when playingthe bounces.